background location config

backgroundLocationTasks.js

import { Permissions, Location, TaskManager, Notifications } from 'expo'
import axios from 'axios'

export const BACKGROUND_LOCATION_UPDATES_TASK = 'background-location-updates'
export const BACKGROUND_GEOFENCING_UPDATES_TASK = 'background-geofencing-updates'
const geofences = [] //I get this from the server, omitted for sake of clarity 
const url = 'api.metoo.io'

TaskManager.defineTask(BACKGROUND_LOCATION_UPDATES_TASK, handleLocationUpdate)
TaskManager.defineTask(BACKGROUND_GEOFENCING_UPDATES_TASK, handleGeofencingUpdate)
export async function initializeBackgroundLocationTasks(){
    try {
        await Permissions.askAsync(Permissions.LOCATION)
        let isBGLRegistered = await TaskManager.isTaskRegisteredAsync(BACKGROUND_LOCATION_UPDATES_TASK)
        if (!isBGLRegistered) await Location.startLocationUpdatesAsync(BACKGROUND_LOCATION_UPDATES_TASK, {
            accuracy: Location.Accuracy.High, timeInterval: 5000, distanceInterval: 10, 
        })
        let isGeofencingRegistered = await TaskManager.isTaskRegisteredAsync(BACKGROUND_GEOFENCING_UPDATES_TASK)
        if (!isGeofencingRegistered) await Location.startGeofencingAsync(BACKGROUND_GEOFENCING_UPDATES_TASK, geofences)
        return true
    } catch (error) {
        return false
    }
}
export async function handleLocationUpdate({ data, error }) {
    if (error) return
    const username = await AsyncStorage.getItem('username')
	if (data) {
        try {
            const { locations } = data
            const res = await axios.get(`${url}/${__DEV__ ? 'dev/' : ''}userlocation/${username}/${JSON.stringify(locations[0].coords)}`)
        } catch (error) {
            console.log('location update error',error)
        }
	}
}
export async function handleGeofencingUpdate({ data: { eventType, region }, error }) {
    if (error) return
    const username = await AsyncStorage.getItem('username')
    const url = eventType == Location.GeofencingEventType.Enter ? 'entered' : 'exited'
    try {
        // const response = await metooApi.sendLocation({ link: JSON.stringify(region), token })
        const response = await axios.get(siccurl(`${url}/${__DEV__ ? 'dev/' : ''}geofence/${username}/${url}/${JSON.stringify(region)}`))
        const body = eventType === Location.GeofencingEventType.Enter ? 'Entered region' : 'Exited region'
        Notifications.presentLocalNotificationAsync({ title: '', body, ios: { sound: true } })
    } catch (error) {
        console.log('geofence error',error)
    }
}

@niv-breez hmm I never got it to work at all in the background (meaning quit, and re-awakened by the OS for a location update) on a standalone so I can't help you there, this is getting beyond my level of expertise. I see you opened an issue with the expo team, that's probably next best thing you can do. Good luck!